"I've got this beautiful panoramic three-dimensional painting of Mars based on Martian photos. It's 30 feet wide. You can pick out every pebble on the Martian landscape. And who'd have dreamed you could do that?"
- Arthur C. Clarke

The citizens of Sirene appear to have little need for advanced electronics; most of their needs are met by the remarkable fecundity of the Titanic littoral. In this case, motive power for their houseboats is provided by large marine animals.

He bent over the rails, peered down into the underwater pens where Toby and Rex, the slaves, were harnessing the dray-fish for the weekly trip to Fan, eight miles north. The youngest fish, either playful or captious, ducked and plunged...

The fish were finally harnessed... The dray-fish strained, the harness tautened, the houseboat moved north.

In 1936, Sir James Gray promulgated the following paradox: dolphins are observed to swim very fast, but if you calculate the available musculature, there is no where near enough power. Yet they do swim fast. Hence the paradox.

In 1960, it was hypothesized that the compliance (it has "give" to it due to the blubber that underlies it) of dolphin skin would delay water flowing over the skin, preventing turbulence. This would greatly reduce the factor of drag, and remove the paradox. More recently, however, it was shown that while dolphin skin reduces drag, it is also true that dolphin musculature provides significantly more power than a human being's - which is what Gray's calculations were based on. So there is no paradox, and yes, there could be dray-fish!

Take a look at the float-home, from Whipping Star, by Frank Herbert, for another way for a marine animal to power a boat.